Permanent oxidative hair coloring products have been used in professional salons and in retail products for use at home for decades. Coloring products typically comprise a tint component and an oxidizing component which are packaged separately and mixed immediately before use. The tint component contains so-called oxidative primary dyes which are small molecules (primary intermediates or couplers) and an alkalizing agent, usually ammonia. These primary dyes react with each other in the presence of an oxidizing agent to form larger, colored molecules. The tint component is thus mixed with the oxidizing component immediately prior to application to the hair to be colored and the resulting mixture is applied on hair usually for 10 to 50 nm. The oxidizing component may be for example a diluted stabilized solution of hydrogen peroxide. The mixture usually has an alkaline pH of between about 9.5 and 10.5.
Because the primary dyes are small enough to migrate into the hair shaft but the resulting colored molecules are too large to easily leave the hair, the resulting coloration is stable and undergo little fading. Furthermore, hydrogen peroxide, especially in the presence of ammonia, is capable of bleaching melanin, so that it is possible to obtain shades which are lighter or darker than the natural colour. Thus oxidative dye compositions comprising ammonia as alkalizing agent are often referred to as permanent hair colorants or “Level 3” hair colorant. Permanent hair colorants are for example marketed under the Koleston Perfect brand name by Wella Professional in Europe. Demi-permanent hair colorants, also referred to as “level 2” colorants, are also typically marketed as two-component systems. They also use primary dyes as in permanent hair colorants but differ in that they use other alkalizing agents than ammonia, in particular alkanolamines such as monoethanolamine (MEA) or aminomethylpropanol (AMP), and usually function at lower concentration of hydrogen peroxide, typically 1 to 3 weight % (w. %) in the mixed product (also referred to as “on-head” composition) compared to 3 to 6 or even higher w. % for permanent “Level 3” colorants. Higher level of hydrogen peroxide are however sometime used when higher level of coloring are sought (up to 8% H2O2 on head for some shade). Other peroxides may also be used for Level 3 bleaching composition, e.g. persulfate, as oxidizing agent. Demi-permanent hair colorants usually cause less melanin bleaching and thus less lift (i.e. removal) of natural hair color. The resulting dyes also penetrate less deeply in the hair shaft so that demi-permanent hair colorants can be less stable than permanent hair colorants. On the other hand, demi-permanent hair colorants are usually also less damaging to the hair structure than permanent hair colorants and the resulting hair color may also be more natural looking. A further advantage is that demi-permanent hair colorant compositions do not have the strong ammonia smell of permanent hair colorant and thus have a better consumer acceptance. A professional brand of demi-permanent dyes in Europe is for example Color Touch® from Wella.
Ammonia-free hair coloring products have been proposed with the goal to provide coloring results close to those obtained with permanent dyes containing ammonia. For example Schwarzkopf has launched in 2009 in Germany a two-component ammonia-free colorant product under the brand name Essensity. The alkalizing agent used is MEA and relatively high level of hydrogen peroxide is used (up to 7.7% on head).
L′Oreal has launched in 2009 in Western Europe a three-component system for professional usage under the brand name INOA. The INOA products comprise a fatty component, a concentrated dye component and an oxidizing component to be mixed immediately before use. The fatty component comprises primarily mineral oil and does not comprise an alkalizing agent. The dye component comprises MEA as alkalizing agent. The 3 components are recommended to be mixed in a 40:16:60 weight ratio.
Several L′Oreal published patent documents disclose compositions more or less related to the INOA products. For example, US2010/0154141A1 assigned to L′Oreal discloses a process for coloring keratin materials comprising: applying to said keratin materials a coloring composition comprising a direct emulsion (A) comprising at least one fatty substance other than fatty acids present in an amount greater than 25% by weight; at least one surfactant; at least one alkaline agent; at least one colored or coloring entity chosen from direct dyes and oxidation dyes; and water in an amount greater than 5% by weight relative to the total weight of the direct emulsion (A); and a composition (B) comprising at least one oxidizing agent. The alkanolamine is preferably chosen from 2-amino-2-methyl-1-propanol and monoethanolamine.
US2010/0223739A2 assigned to L′Oreal discloses a process and kit for coloring or dyeing keratin fibers, in which the following are applied to the fibers: an aqueous cosmetic composition (A) comprising at least one fatty substance and at least one surfactant; a cosmetic composition (B) comprising at least one alkaline agent, a cosmetic composition (C) comprising at least one oxidizing agent, wherein the amount of the at least one fatty substance in composition (A) is greater than 20% by weight relative to the total weight of composition (A), and when the process used is a process for dyeing keratin fibers, then cosmetic composition (B) further comprises at least one oxidation dye, at least one direct dye, or both.
Further patent applications assigned to L′Oreal disclose coloring compositions obtained by mixing three components. For example US2009/0191142 discloses a process for dyeing human keratin fibers in the presence of at least one oxidizing agent, comprising applying to the fibers at least one anhydrous composition (A) comprising at least one fatty substance and at least one surfactant, at least one composition (B) comprising at least one oxidizing agent, and at least one composition (C) comprising at least one dye chosen from direct and oxidation dyes, and at least one organic amine having a pKb at 25° C. of less than 12. The disclosure also relates to a multi-compartment device containing, in separate compartments, the compositions (A), (B), and (C); and a method of making a ready-to-use composition. The present disclosure also relates to an anhydrous composition comprising at least one fatty substance, at least one surfactant, at least one dye, and at least one organic amine. L′Oreal's US2009/0162309, US2009/0158533, US2010/0175705, US2010/0175706, US2010/0178264, US2010/0154137 also disclose 3 components coloring compositions.
US2008/0052841A1 assigned to LES PRODUITS VERNICO LTEE discloses a method for permanently modifying a color of keratinous fibers with a mixture of three compositions A, B and C, wherein said composition A comprises at least a reducing agent and optionally a coloring compound, said composition B comprises at least an alkalizing compound and said composition C comprises at least an oxidizing compound.
U.S. Pat. No. 6,423,101, assigned to EUGENE PERMA discloses an ammonia-free composition for dyeing keratinous fibers, comprising an oxidant compound, coloring agent precursors and a non-volatile odorless alkalizing agent characterized in that it further comprises: a quaternized copolymer of dimethyldiallyl ammonium and acrylic acid; a quaternized silicone; and an acrylic-itaconic copolymer esterified with one or several fatty alcohol's, optionally polyoxyethylenated. The composition is prepared using a two-component system with MEA as alkalizing agent. According to this Patent, the specific ternary complex claimed provides coloration which gives good coverage and resistance similar to coloration using ammonia.
Although the prior art discloses using two- or three-component systems to obtain a permanent hair coloring result without ammonia, this has usually been obtained by the use of higher level of hydrogen peroxide, which can result in relatively higher damages to the hair fibers, especially after repeated treatments. Furthermore, the prior art has not provided a versatile system for providing different level of lift at the discretion of the user based a single tint component.
The present inventors have now surprisingly found that it was possible to formulate high lift coloring compositions based on a non-ammonia alkalizing agent while keeping hair damage to acceptable level. The inventors have found that increasing the weight ratio of the non-ammonia alkalizing agent to hydrogen peroxide provided improved results. This increased ratio can be obtained using a two-component system, in which case the tint component may be provided with higher than usual level of non-ammonia alkalizing agent. The inventors have also found that the lift provided by typical two-component demi-permanent coloring products can be increased by mixing them with a third component comprising a non-ammonia alkalizing agent, while keeping the damage at acceptable level. The compositions of the invention can provide similar level of lift and/or intensity of coloration but at lower hair fiber damage level than compositions with higher level of hydrogen peroxide.